#+TITLE:Org Cheatsheat
#+AUTHOR: Joshua Branson
# I'm not liking the latexpreview #+STARTUP: latexpreview
#+LANGUAGE: en
#+HTML_HEAD <link rel="stylesheet" type="text/css" href="stylesheet.css" />
# The next lines says that I can make 10 levels of headlines, and org will treat those headlines as how to structure the book into
# chapters, then sections, then subsections, then sub-sub-sections, etc.
* Movement commands
  - ~C-c C-n~ Next heading
  - ~C-c C-p~ Previous heading
  - ~C-c C-u~ backward to a higher level heading
  - ~C-c C-j~  org-goto...it is super nice!!
* "TODO" notes
  Org mode has some VERY handy ways of keeping track of todo items.

** The Default TODO/DONE state
   When point is on a heading, pressing "C-c C-t" when insert a TODO at the begining of the line, indicatating that it is an item that
   needs to be completed.  Pressing "C-c C-t" changes the TODO "DONE".  You can change the default values as well.

** You can also break tasks into neat little subtasks.  And keep track of how much of the task is done!

*** TODO Take over the world [20%]
    :LOGBOOK:
    - State "TODO"       from              [2015-10-31 Sat 20:20]
    :END:

**** TODO Get some converts [1/2]
     :LOGBOOK:
     - State "TODO"       from              [2015-10-31 Sat 20:20]
     :END:

***** TODO Talk to people [66%]
      :LOGBOOK:
      - State "TODO"       from              [2015-10-31 Sat 20:20]
      :END:

****** DONE Kyle
       CLOSED: [2015-10-31 Sat 20:22]
       :LOGBOOK:
       - State "DONE"       from "TODO"       [2015-10-31 Sat 20:22]
       - State "TODO"       from              [2015-10-31 Sat 20:20]
       :END:

****** TODO Jen
       :LOGBOOK:
       - State "TODO"       from              [2015-10-31 Sat 20:20]
       :END:

****** DONE Juice
       CLOSED: [2015-10-31 Sat 20:21]
       :LOGBOOK:
       - State "DONE"       from "TODO"       [2015-10-31 Sat 20:21]
       - State "TODO"       from              [2015-10-31 Sat 20:21]
       :END:

***** DONE Write some web blogs
      CLOSED: [2015-10-31 Sat 20:22]
      :LOGBOOK:
      - State "DONE"       from              [2015-10-31 Sat 20:22]
      :END:
**** TODO Get some $$$  [33%]
     :LOGBOOK:
     - State "TODO"       from              [2015-10-31 Sat 20:20]
     :END:
***** DONE Rob a bank
      CLOSED: [2015-10-31 Sat 20:21]
      :LOGBOOK:
      - State "DONE"       from "TODO"       [2015-10-31 Sat 20:21]
      - State "TODO"       from              [2015-10-31 Sat 20:21]
      :END:
***** TODO start a business
      :LOGBOOK:
      - State "TODO"       from              [2015-10-31 Sat 20:21]
      :END:
***** TODO sell my stuff
      :LOGBOOK:
      - State "TODO"       from              [2015-10-31 Sat 20:22]
      :END:
**** DONE Overthrow the government
     CLOSED: [2015-10-31 Sat 20:22]
     :LOGBOOK:
     - State "DONE"       from "TODO"       [2015-10-31 Sat 20:22]
     - State "TODO"       from              [2015-10-31 Sat 20:20]
     :END:

**** TODO help the common man
     :LOGBOOK:
     - State "TODO"       from              [2015-10-31 Sat 20:20]
     :END:

**** TODO kill all the remaining zombies [1/2]
     :LOGBOOK:
     - State "TODO"       from              [2015-10-31 Sat 20:20]
     :END:

***** DONE kill the zombies in Africa
      CLOSED: [2015-10-31 Sat 20:23]
      :LOGBOOK:
      - State "DONE"       from              [2015-10-31 Sat 20:23]
      :END:

***** STARTED kill the zombies in NY
      :LOGBOOK:
      - State "STARTED"    from              [2015-10-31 Sat 20:23]
      :END:

** You can also create little checkboxs too!

*** TODO shopping [2/3]
    :LOGBOOK:
    - State "TODO"       from              [2015-10-31 Sat 20:24]
    :END:

    - [ ]  pickles

    - [X] onions

    - [X] lettuce
* Getting familiar with org-agenda
** commands
   - ~v d~  or ~d~  shows’ today’s agenda
   - ~v w~  or ~w~ shows this week’s agenda
   - ~v m~  view this month’s agenda
   - ~v t~  shows the fortnight
   - ~.~  goto today’s agenda
   - ~j~  goto a specified date
   - ~J~ goto the currently clocked in task
   - ~v c~  shows you overlapping clock entries
   - ~r~ redraw the agenda buffer
   - ~C-k~  kill the current agenda item in the agenda buffer and in the file
   - ~C-c C-w~ refile the entry
   - ~T~ show the tags of an entry
   - ~:~ set the tags for the current entry
   - ~,~  set the priority of the item
   - ~P~  show the priority of the item
   - ~+~ Increase its priority
   - ~-~ minus its priority
   - ~z~ add a note to the entry
   - ~>~ change the timestamp with that entry
   - ~I~ clock in on an entry
   -  ~O~ clockout on an entry
   - ~X~ cancel the current running clock
   - ~m~ mark the entry at point
   - ~u~ undo the marked point
   -  ~U~ unmark all marked entries
   - ~%~ mark via regexp
** views
   - (org-agenda-log-mode)  enteries that were marked done while logging was on, are shone in hte agenda, as are
     entries that have been clocked today.
   - (org-agenda-clockreport-mode) the agenda view will show a table with all your currently clocked time on tasks.
   - (org-agenda-entry-text-mode)
* export commands
  In an org buffer type C-c C-e and org-mode will open a buffer that will prompt you for how you would like to export your document.
** Export Settings
   [[info:org#Export%20settings][info:org#Export settings]]
   Export options can be set globally with variables, but its much easier to specify your export options in your org buffer

   For example
   =#+OPTIONS: toc:nil DATE:<2015-11-20 Fri>=  will not export your table of contents and specifies an export date
   =+TOC:nil=  does nothing

   - = Trees with the tag =:noexport:= means they won't be exported
* Org babel
    :PROPERTIES:
    :engine: mysql
    :dbhost: localhost
    :dbuser: root
    :dbpassword: <your password here>
    :database: usbc
    :END:
  Org babel allows you to insert code blocks into a document.  Those code block's results, can be /weaved/ to html, latex, info,
  etc OR that code can be /tangled/ to be later run by a computer!  It super cool because inside one emacs buffer, you can be writing
  a program that uses 30 different languages, and each block's results can be used as input to any other block!
  - An sql example

#+BEGIN_SRC org
  :PROPERTIES:
  :engine: mysql
  :dbhost: localhost
  :dbuser: root
  :dbpassword: <your password here>
  :database: usbc
  :END:
#+END_SRC

** sql
    #+name: my_query
    # results output and exports both let the exported file show both the code and the results in the exported file
    #+BEGIN_SRC sql :results output :exports both
      SELECT first, last FROM users WHERE last = 'Branson' limit 5
    #+END_SRC

    #+RESULTS: my_query
    | first  | last    |
    |--------+---------|
    | Joshua | Branson |
    | Joshua | Branson |
    | Joshua | Branson |
    | Joshua | Branson |

    That "my_query" block can be passed as input to the following code block
    #+BEGIN_SRC emacs-lisp :var x=my_query
      (print x)

    #+END_SRC

    #+RESULTS:
    | Joshua | Branson |
    | Joshua | Branson |
    | Joshua | Branson |
    | Joshua | Branson |

    One can also tell emacs NOT to export the results of a code execution via
    #+BEGIN_SRC emacs-lisp :exports none
      (print "hello")
    #+END_SRC

    #+RESULTS:
    : hello

    This just mean that when you export the document to html, pdf, .odt, etc., then you will not see that code block's source code or results.

  - A gnu plot example

    #+BEGIN_SRC gnuplot
    set title "My First Plot";  plot 'data';  print "all done!"
    #+END_SRC
** gnu calc
   #+BEGIN_SRC calc
     fsolve (x*2 + 4 = 5, x)
   #+END_SRC

   #+RESULTS:
   : x = 0.5

   #+BEGIN_SRC calc
   fsolve([x + y = a, x - y = b],[x,y])
   #+END_SRC

   #+RESULTS:
   : [x = a + (b - a) / 2, y = (a - b) / 2]

  #+BEGIN_SRC calc
  integ (x**2,x)
  #+END_SRC

  #+RESULTS:
  : x^3 / 3

** gnuplot
   #+BEGIN_SRC gnuplot
   plot x**2 with lines
   #+END_SRC

   #+RESULTS:

** running code remotely
    :PROPERTIES:
    :dir: /ssh:user@host.com:/home/user
    :END:
    #+BEGIN_SRC sh :dir /<user>@<host>:/path/to/file
      ls
    #+END_SRC

** C code
More documentation can be found here:  https://orgmode.org/worg/org-contrib/babel/languages/ob-doc-C.html#org966170f

I could try to get this documentation included into the Emacs manual.


#+BEGIN_SRC C :includes '("<stdio.h>" "<math.h>") :flags -lm :defines MAX_NUMBER 128

  /* This function takes an int and prints its binary representation */
  int return_b_number (int i)
  {
    /* find the highest power of 2 <= i */
    short int n = 0;
    for (; pow(2 , n) <= i; ++n)
      {

      }
    printf("%d\n", n);

  }

  int main ()
  {
    return_b_number (33);
    return 0;
  }
#+END_SRC

#+RESULTS:
: 6

   #+BEGIN_SRC C :exports both :includes <math.h> :flags -lm :var x=1.0 y=4.0 z=10.0
     double pi = 4*atan(1);
     double r, theta, phi;
     r = sqrt(x*x+y*y+z*z);
     theta = acos(z/r) * 180.0/pi;
     phi = atan2(y,x) * 180.0/pi;
     printf("%f %f %f", r, theta, phi);
   #+END_SRC

   #+RESULTS:
   : 10.816654 22.406871 75.963757

   To include multiple C header files
   #+BEGIN_SRC C :includes <math.h> <time.h>
   int b;
   #+END_SRC

   #+RESULTS:

   Finding delimiters in a string
    #+BEGIN_SRC C  :includes <string.h>
    const char * string = "<html><body><title>Hello World</title><p>Hello World</p></body></html>";

    const char delimiters[] = "<>";
    char *token, *cp;

    cp = strdup (string);                /* Make writable copy.  */
    token = strtok (cp, delimiters);      /* token => "words" */
    printf("%s\n", token);

    token = strtok (NULL, delimiters);      /* token => "words" */
    printf("%s\n", token);

    token = strtok (NULL, delimiters);      /* token => "words" */
    printf("%s\n", token);
    #+END_SRC

    #+RESULTS:
    | html  |
    | body  |
    | title |

** org mode
   Sometimes you may need to generate org-mode source code inside your document for exporting. So to do that you do:

   #+BEGIN_SRC org
    #+BEGIN_SRC python
     print "foo"
    ,#+END_SRC
   #+END_SRC
** simple calc example
   :PROPERTIES:
   :DATE:     2011-01-25
   :END:
#+begin_src calc
2*3
#+end_src

#+name:
: 6
** lisp
   :PROPERTIES:
   :DATE:     2010-08-12
   :END:

#+begin_src lisp :var n=5
  (mapcar (lambda (el) (* el el)) (append '(1 7 3 4) (list n)))
#+end_src

#+name:
| 1 | 49 | 9 | 16 | 25 |

#+name: short-list
| 1 |
| 2 |
| 3 |

#+begin_src lisp :var lst=short-list :session t
  (+ 1 (length lst))
#+end_src

#+name:
: 4

** bash
  #+begin_src sh
    echo "This file takes up `du -h org-babel.org |sed 's/\([0-9k]*\)[ ]*org-babel.org/\1/'`"
  #+end_src

  #+RESULTS:
  : This file takes up

  #+begin_src sh
    pacman -Q firefox
  #+end_src

  #+RESULTS:
  : firefox 41.0.1-1

  This program lists duplicate files.  It runs md5sum on the files to find the duplicates
  https://www.maketecheasier.com/remove-duplicate-files-linux/
  #+BEGIN_SRC sh :dir ~/manuals/
  find -not -empty -type f -printf "%s\n" | sort -rn | uniq -d | xargs -I{} -n1 find -type f -size {}c -print0 | xargs -0 md5sum | sort | uniq -w32 --all-repeated=separate
  #+END_SRC

  #+RESULTS:
  | 2a44284ee46b6572872e5c704889eba4 | ./emacs.org                                               |
  | 2a44284ee46b6572872e5c704889eba4 | ./emacs.org.backup                                        |
  |                                  |                                                           |
  | 7ac95b56101e570db018311e775b7952 | ./ltxpng/org_8efa66ec78ea83e97f9815c08a43ee880750b6ee.png |
  | 7ac95b56101e570db018311e775b7952 | ./ltxpng/org_e7d761bed1cade664f3496421252f6aebdf30781.png |



  In this example both the lisp code and the results will be exported:

  #+BEGIN_SRC emacs-lisp :exports both
  (print "hello")
  #+END_SRC

  #+RESULTS:
  : hello


 #+BEGIN_SRC emacs-lisp

 #+END_SRC

** [[http://kitchingroup.cheme.cmu.edu/blog/2016/02/09/Calling-remote-code-blocks-in-org-mode/?utm_source=feedburner&utm_medium=twitter&utm_campaign=Feed:+TheKitchinResearchGroup+(The+Kitchin+Research+Group)#hallenbeck-2015-compar-co2][calling remote code blocks]]
So, we make a named code block in the si.org file called "figure-1". Then we call it like this:

#+BEGIN_SRC org
  ,#+call: si.org:figure-1() :wrap html
#+END_SRC

** http
[[https://github.com/zweifisch/ob-http][ob-http]] mode
#+BEGIN_SRC http :pretty
GET https://api.github.com/repos/zweifisch/ob-http/languages
Accept: application/vnd.github.moondragon+json
#+END_SRC

#+RESULTS:
: {
:   "Shell": 139,
:   "Emacs Lisp": 13293
: }

** header arguments [[info:org#Specific%20header%20arguments][info:org#Specific header arguments]]
*** :var
:var [<variable name>=<[ literal_value | #+table_name ]>]  [<variable name>=<[ literal_value | #+table_name ]>] ...

**** :var lets you assign a variable at the top level header argument.
#+BEGIN_SRC calc :var x=5 y=6 z=50
x + y + z
#+END_SRC

#+RESULTS:
: 61

#+NAME:GAS
#+BEGIN_SRC calc
1.89
#+END_SRC

#+RESULTS: GAS
: 1.89

#+RESULTS:
: 1.89

***** you can assign a variable to the result of an org src code block
5 gallons of gas costs
#+BEGIN_SRC calc :var gas=GAS
5 * gas
#+END_SRC

#+RESULTS:
: 9.45

*** :dir
#+BEGIN_SRC sh :dir ~/manuals :results output
ls | grep -m 5 -e ".*org" -
#+END_SRC

#+RESULTS:
: accrisoft.org
: apache.org
: arch.org
: auto-complete.org
: bash.org

*** :output-dir
*** :exports
:exports [both | results | code | none]

Export specifies what needs to be saved when you export the document
** passing specific org table columns
#+NAME: output
| groceries |  50 |
| rent      | 800 |
| debt      | 500 |
| electric  | 100 |
|-----------+-----|

#+BEGIN_SRC sh :results output :var name=output[,0]
  for output in $name; do
      echo $name
  done
#+END_SRC

#+RESULTS:
: groceries rent debt electric
: groceries rent debt electric
: groceries rent debt electric
: groceries rent debt electric
** using multiple languages


#+NAME: mynewformula
#+BEGIN_SRC calc
2+a*x**y
#+END_SRC

#+RESULTS: mynewformula
: a x^y + 2

#+CALL: mynewformula(x=10,y=2,a=2)

#+RESULTS:
: 202

* Org spreadsheets/tables

|-------------------------+-----------+-----------+-------|
| Money I earn in a month | Expenses  | Expenses$ | Total |
|-------------------------+-----------+-----------+-------|
|                    2000 | groceries |       500 |       |
|                     100 | gas       |       200 |       |
|-------------------------+-----------+-----------+-------|
|                         |           |       700 |       |
|-------------------------+-----------+-----------+-------|
#+TBLFM: $3=@2$3+@3$3


One refers to a specific table in org, @ROW$COLUMN.  Sometimes its hard to see the column and row values.  To show these, anywhere in the table type =C-c }=. Typing =C-c }= again, will turn hide the row and column values.  You can add columns fairly easily.  For example, let's sum my expenses for the month: at the bottom of my expenses row, type in ~=@2$3 + @3$3~


But let's say that you have lots of expenses.  How can I add a range of values? in the total section under expenses type:
~=vsum(@2$3..@5$3)~
|-------------------------+---------------+-----------+-------|
| Money I earn in a month | Expenses      | Expenses$ | Total |
|-------------------------+---------------+-----------+-------|
|                    2000 | groceries     |       500 |       |
|                     100 | gas           |       200 |       |
|                     800 | rent          |       450 |       |
|                      20 | entertainment |        20 |       |
|-------------------------+---------------+-----------+-------|
|                         |               |      1170 |       |
|-------------------------+---------------+-----------+-------|
#+TBLFM: $3=vsum(@2$3..@5$3)

** Commands
   - =C-c *= recalculates that table row
   - =C-}= toggles showing the row and column numbers
   - =C-{= toggles formula debugging
   - =C-c |= convert the active region to a table
   - =TAB= moves you to the next column
   - =S-TAB= takes you back to the last column
   - =org-table-delete-column= deletes the column point is in
   - =C-c -= insert a horizontal line below point
   - =C-c SPC= blank the field at point
   - =M-left= move column to the left
   - =M-right= move column to the right
   - =C-c '= edit the field in a seperate window=
   - =C-c SPC= blank the field at point
   - =C-c <RET>= insert a horizontal row below point
   - =C-c ^= sort the current table, by the column that point is in alphabetically or numerically SUPER COOL.
* Org Columns
  When in an org file, you can change the file to column view.  You can define a custom column format for the whole file with:
  #+BEGIN_SRC org
    ,#+COLUMNS: %25ITEM %TAGS %PRIORITY %TODO
  #+END_SRC

  You can define a column view for a specific subtree with
  #+BEGIN_SRC org
    ,** Top node for columns view
       :PROPERTIES:
       :COLUMNS: %25ITEM %TAGS %PRIORITY %TODO
       :END:
  #+END_SRC
* org lists

#+BEGIN_SRC org
  ,* hello there you cool people
  ,* hello  C-RET will make a new item in this list
  ,* here is that new item!
#+END_SRC

When you have a list like the one above, to add to it just type C-RET, but when you have a list like the one below, you need to type M-RET.

#+BEGIN_SRC org
  1) tahsetnhaentuh
  2) snthaoentuhesntuh
  3)
  4)
  5)
  6)

  This paragraph would mess up your list.  If you try to start a new list here, org will assume that it should start at "1)".  To fix it, you have to include the =[@<number>] text  [@<number>]=.

  7) [@7] sntahenusth [@7]
  8)
#+END_SRC
* latex equations

  \[
  \hat{F}(\nu) = \frac{G(\nu)}{H(\nu)}.
  \]

  There are other ways that I'm supposed to be able to make latex fragments
  If $a^2=b$ and \( b=2 \), then the solution must be
     either $$ a=+\sqrt{2} $$ or \[ a=-\sqrt{2} \].

     \begin{equation}
     x=\sqrt{b}
     \end{equation}

  org-preview latex fragment with "C-c C-x C-l"



\begin{equation} R=-µ\fraq{du_{x}}{dy} \end{equation}

* Creating Indexes
  You can specify entries that will be used for generating an index during
  publishing.  This is done by lines starting with `#+INDEX'.  An entry
  the contains an exclamation mark will create a sub item.  See *note
  Generating an index:: for more information.

     * Curriculum Vitae
     #+INDEX: CV
     #+INDEX: Application!CV

* Agenda
** Agenda commands
   - =A= redraw the agenda view and prompt for how you want it
   - =d= show the day's view
   - =w= show the week's view
   - =f= go forward in time
   - =b= go backward in time
   - =j= jump to a specific date
   - =.= jump to today
   - =D= toggle inclusion of diary entries
   - =vl= toggle logbook mode.
   - =vR= will toggle clockreport mode.  You will see a table showing you the total amount of time
   - =vc= show overlaping clock entries, clocking gaps, or other clocking problems. Then press l to return to the normal
     agenda view
   - =G= toggle displaying of the time grid in the view
   - =g/r= redraw the agenda buffer
   - =/= filter by tag
   - =\= narrow the agenda buffer further by another tag
   - ~=~ filter the agenda view by regexp
   - =|= remove all filters on the agenda view
   - =a= archive the item at point
   - =T= show the tags associated with the current item
   - =:= set the tags for the current item
   - =,= set the priority of the item
   - =z= add a note to this entry
   - =C-c C-s= attach an item to this item
   - =I= clock in
   - =m= mark the agenda item
   - =u= unmark the item
   - =U= unmark all items
   - =%= mark all entries via a regexp
   - =B= do a bulk action on the marked items in the agenda

   When inside the calendar/agenda
   - =i= insert a new entry into the diary
   - =M= show the date phases of the moon
   - =S= show sunrise and sunset times
   - =H= show upcoming Holidays
   - =
* inserting links
** a bbdb record link into the file
    [[bbdb:Nathaniel Simone]]
    How cool is that?

To do this "C-c I" bbdb RET <name of person>
** an email address
[[mailto:bransoj@hotmail.com][my email address]]

To do this "C-c I" mailto RET <email address>
** gnus links!!!???
* Putting images in the document
Create some markup like this:

#+BEGIN_SRC org
  ,#+CAPTION: Which key displays the current major mode's keybindings
  ,#+NAME:   fig:which-key
  [[file:./images/speedtest.net.png]]
#+END_SRC

Then "C-c C-x C-v" will display the inline image.

You could also customize the variable: ‘org-startup-with-inline-images’.

Alternatively you could specify an org variable at the top of your document.

#+CAPTION: Which key displays the current major mode's keybindings
#+NAME:   fig:which-key
[[~/.emacs.d/images/which-key.png]]
* Easy Templates
  Org mode supports insertion of empty structural elements (like #+BEGIN_SRC and #+END_SRC pairs) with just a few key strokes. This is achieved through a native template expansion mechanism. Note that Emacs has several other template mechanisms which could be used in a similar way, for example yasnippet.

To insert a structural element, type a ‘<’, followed by a template selector and <TAB>. Completion takes effect only when the above keystrokes are typed on a line by itself.

The following template selectors are currently supported.

- s 	#+BEGIN_SRC ... \\ #+END_SRC
- e 	#+BEGIN_EXAMPLE ... \\ #+END_EXAMPLE
- q 	#+BEGIN_QUOTE ... \\ #+END_QUOTE
- v 	#+BEGIN_VERSE ... \\ #+END_VERSE
- c 	#+BEGIN_CENTER ... \\ #+END_CENTER
- l 	#+BEGIN_LaTeX ...  \\ #+END_LaTeX
- L 	#+LaTeX:
- h 	#+BEGIN_HTML ...  \\ #+END_HTML
- H 	#+HTML:
- a 	#+BEGIN_ASCII ... \\ #+END_ASCII
- A 	#+ASCII:
- i 	#+INDEX: line
- I 	#+INCLUDE: line

For example, on an empty line, typing "<e" and then pressing TAB, will expand into a complete EXAMPLE template.

You can install additional templates by customizing the variable org-structure-template-alist. See the docstring of the variable for additional details.
* Categories
  I can specify Categories to show up nicely in the agenda buffer
  Right under a tree item, I can say

  #+BEGIN_SRC org
    ,* Good Jokes
      :PROPERTIES:
      :CATEGORY: Projects
      :END:
    ,** One time this farmer
  #+END_SRC
* Schedulting

Scheduling involves creating timestamps.  An active timestamp is enclosed by "<" and ">", and it will cause the heading it's in, to show up in the agenda buffer.  An inactive timestamp is enclosed by "[" "]" and it will not show up in the agenda buffer.
  You can schedule to begin working on a TODO item by typing C-c C-s.  You can schedule a deadline for a TODO item by typing C-c C-d.

  The result is this

  #+BEGIN_SRC org
    ,* TODO Walk the dog
      SCHEDULED: <2015-11-23 Mon>
  #+END_SRC

  You can also make items repeatable like so.  This tasks repeats everyday and lets you know if you miss it.

  #+BEGIN_SRC org
    ,* TODO Walk the dog
      SCHEDULED: <2015-11-23 Mon +1d>
  #+END_SRC

  However the above is not satisfactory.  Org-mode provides two nice extensions to this.

  The below reminds you to take out your trash once a week.  BUT if you forget to do it, it'll still make you take it out on Monday.
  The + sign is a precise mathematical operation. It precisely remembers the day to do this task.

  #+BEGIN_SRC org
    ,* TODO Take out the trash
      SCHEDULED: <2015-11-23 Mon ++1w>
  #+END_SRC


  The below reminds you to brush your teeth.  BUT if you forget to do it, it'll still tell you do it the next 3rd day.
  The . is a regexp symbol that can is a variable.  In the same way, the day that you do this task is variable.

  #+BEGIN_SRC org
    ,* TODO Work out
      SCHEDULED: <2015-11-23 Mon .+3d>
  #+END_SRC

  You can also say that you want to do something at least every third day but at most every fourth day like this

  #+BEGIN_SRC org
    ,* TODO workout
       SCHEDULED: <2015-11-26 Thu .+3d/4d>
  #+END_SRC

  # I got this text from: [[info:org#Repeated%20tasks][info:org#Repeated tasks]]
  To mark a task with a repeater as `DONE', use `C-- 1 C-c C-t' (i.e.,
`org-todo' with a numeric prefix argument of -1.)
** Advanced Scheduling

Org scheduling will only get you so far.  Org timestamps cannot plan things like "The 2nd Thursday of the Month", but the Emacs Diary Sexp Entries can!

For example,  suppose your local bowling team goes bowling on the 3rd Tuesday of every month.  Here is how you can schedule that task:

#+BEGIN_SRC org
  ,*  Go Bowling with the Gents
   <%%(diary-float t 2 3)>
#+END_SRC

If you would like to know more, the documentation for the function "diary-float", is quite sufficient.
* inactive timestamps

Inactive timpstamps can be inserted into the document via: "C-c !".  But they can't be because "C-c !" is flyspell's keybinding.
Maybe I should make a keybinding for inserting an inactive timestamp into the document.
* parsing an org file

#+BEGIN_SRC emacs-lisp
  (setq my/ast (with-temp-buffer
                 (insert-file-contents "~/file.txt")
                 (org-mode)
                 (org-element-parse-buffer)))
#+END_SRC

The elisp function is org-element-parse-buffer &optional GRANULARITY VISIBLE-ONLY  ...

granularity can be any of the following:

|-----------------+-----------------------------------|
| headline        | only parse headlines...           |
| greater-element | only parse the top level elements |
| elements  parse | all but objcets and plain text    |
| object          | parse all stuff                   |
|-----------------+-----------------------------------|

visible-only means don't parse contens of hidden elements...
